The present invention relates generally to acoustic transducers, and, more particularly, to acoustic dampers for acoustic transducers.
Transducers, and particularly microphones, are typically utilized in hearing aids. Generally, electret transducers comprise a housing having an opening, inlet, that communicates with the interior of the housing. An electret motor assembly including a diaphragm adjacent a charged plate having an electret material formed thereon is mounted within the housing to define acoustic chambers on opposite sides of the motor assembly.
An acoustic signal enters one of the chambers via the inlet of the housing, allowing the diaphragm to respond thereto. Air pulsations created by the vibrations of the diaphragm pass from one acoustic chamber to the other acoustic chamber.
The electret material on the charged plate is operably connected to electronic circuitry to permit electroacoustical interaction of the diaphragm and electret material on the backplate to create an electrical signal representative of the acoustic signal. As is known, the converse operation may be provided by the transducer in that an electrical signal may be applied to the electret on the backplate to cause the diaphragm to vibrate and thereby to develop an acoustic signal that can be coupled out of the acoustic chamber.
Common in microphones, a port tube extends from or is integral with the inlet of the housing and provides acoustic resistance to the acoustic signal before it reaches the diaphragm. However, it is preferable that a hearing aid have the smallest dimensions possible, and a port tube increases the overall size of the microphone.
An acoustic transducer in accordance with the present invention provides an inexpensive and simple solution to eliminate the drawbacks of the prior acoustic transducers.
One embodiment of the present invention is directed to an acoustic damper for a transducer. The transducer comprises a housing having an inlet. The damper has a mesh panel and non-mesh periphery wherein the mesh panel covers the inlet. The non-mesh periphery of the damper is attached to the housing with an adhesive. The non-mesh periphery inhibits the adhesive from wicking into the mesh panel.
Another embodiment of the present invention includes a film operably attached to the non-mesh periphery of the damper. The film and the damper form a diaphragm assembly. The interior of the film is free to move without touching the mesh panel. The diaphragm assembly is adaptable for cooperating with a backplate to form a motor assembly.
One object of the present invention is to provide an acoustic damper having a reduced dimension for a transducer.
Another object of the present invention is to provide a diaphragm assembly having an acoustic damper, the diaphragm assembly capable of being adapted to a motor assembly of a transducer.